Seventh nuclear reactor in South Korea down due to glitches

The number of out-of-order nuclear reactors at South Korea’s power plants has increased to seven after a power turbine went down at Hanbit due to a glitch.

After a similar incident in Kori last week and a streak of shutdowns related to forged safety documents, almost a third of South Korea’s nuclear power stations are now off-line, putting the security and reliability of electricity supplies during the upcoming winter at risk.

"Halting nuclear power units is part of normal operation for safety. But power supply will have problems," said a spokesman at operator Korea Hydro & Nuclear Power (KHNP).

KHNP is investigating the cause of the shutdown that affected the power turbine of the 1,000-megawatt Hanbit 3 reactor, some 250 km southwest of Seoul.

At the same time, maintenance at the Hanbit 4b reactor has been extended by additional two or three weeks to mid-January from a planned return to operation on 1 January.

The operator decided to extend the shutdown to repair cracks found on the reactor head during regular check-ups.

South Korea, the fourth largest economy in Asia, with its 23 nuclear power stations relies heavily on nuclear power to meet its energy needs. About one third of South Korea’s electricity is generated in nuclear power plants

After the latest incident, the pressure on the country’s authorities will grow to secure sufficient electricity supplies.

The number of shut-down reactors could possibly further increase as maintenance has been scheduled to start at another reactor at Hanbit in mid-December.

Of the nuclear power generators that are now offline, three have been shut since late May because of control cables supplied with fake safety certificates, according to the KHNP spokesman.

A fourth is awaiting an extension of its license after its 30-year life span expired in November last year; the fifth is the unit with the extended maintenance period; and a sixth was shut automatically last Thursday due to a technical glitch.

The schedule for the restart of the sixth is still not clear, the KHNP spokesman said.